# Relationship history for MSHA mine 2600429

Current hierarchy: **CRH PLC → Staker & Parson Cos. → Boehler Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Ball Construction Company → Boehler Pit; 1950-01-01 to 1978-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Ball Construction Company → Boehler Pit; 1950-01-01 to 1978-08-14; source msha-controller-operator-history
- **controller_controls_operator:** Ball Construction Company → Ball Construction Company; 1950-01-01 to 1978-08-14; source msha-controller-operator-history
- **operator_operates_mine:** Boehler Construction Inc → Boehler Pit; 1978-08-15 to 2006-08-13; source msha-controller-operator-history
- **controller_controls_mine:** Mahlon  Boehler → Boehler Pit; 1978-08-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mahlon  Boehler → Boehler Construction Inc; 1978-08-15 to 2006-08-13; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Boehler Pit; 2002-05-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Staker & Parson Cos. → Boehler Pit; 2006-08-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Staker & Parson Cos.; 2006-08-14 to current/open; source msha-controller-operator-history